Radio communication system and mobile station device

ABSTRACT

A mobile station device transmits a random access preamble to a base station device and performs uplink timing alignment based on the synchronization timing deviation information included in a random access response which the base station device transmits in response to the transmitted random access preamble, wherein in an uplink synchronous status, the mobile station device does not perform uplink timing alignment based on synchronization timing deviation information included in a random access response, which is a response to a random access preamble whose preamble ID is randomly selected by the mobile station device.

This application is a Divisional of co-pending application Ser. No.12/529,160 filed on Aug. 28, 2009, which is a National Phase ofPCT/JP2008/064217 filed on Aug. 7, 2008, and for which priority isclaimed under 35 U.S.C. §120; and these applications claim priority ofApplication No. JP2007-207213 filed in Japan on Aug. 8, 2007, under 35U.S.C. §119; the entire contents of all are hereby incorporated byreference.

TECHNICAL FIELD

The present invention relates to radio communication systems and mobilestation devices.

The present application claims priority on Japanese Patent ApplicationNo. 2007-207213 filed Aug. 8, 2007, the content of which is incorporatedherein by reference.

BACKGROUND ART

In the 3GPPP (3rd Generation Partnership Project), the W-CDMA (WidebandCode Division Multiple Access) system has been standardized as the thirdgeneration cellular mobile communication system so as to sequentiallylaunch services. In addition, the HSDPA (High Speed Downlink PacketAccess) system has been standardized so as to launch services.

The 3GPP is considering the evolution of third-generation radioaccessing (EUTRA: Evolved Universal Terrestrial Radio Access). Itproposes the OFDM (Orthogonal Frequency Division Multiplexing) system asthe downlink of EUTRA. It also proposes a single carrier communicationsystem based on the DFT (Discrete Fourier Transform)-spread OFDM systemas the uplink of EUTRA.

FIG. 9 is an illustration showing uplink and downlink channelconfigurations for EUTRA. A base station device (BS) transmits data tomobile station devices (MS1, MS2, MS3, etc.) by use of downlinks. Themobile station devices (MS1, MS2, MS3, etc.) transmit data to the basestation device (BS) by use of uplinks.

The downlink of EUTRA include a downlink pilot channel (DPiCH: DownlinkPilot Channel), a downlink synchronization channel (DSCH: DownlinkSynchronization Channel), a downlink control channel (PDCCH: PhysicalDownlink Control Channel), a common control channel (CCPCH: CommonControl Physical Channel), and a downlink shared channel (PDSCH:Physical Downlink Shared Channel).

The uplink of EUTRA include an uplink shared channel (PUSCH: PhysicalUplink Shared Channel), an uplink control channel (PUCCH: PhysicalUplink Control Channel), a random access channel (RACH: Random AccessChannel), and an uplink pilot channel (UPiCH: Uplink Pilot Channel) (seeNon-Patent Documents 1, 2).

FIG. 10 is a chart showing an example of an uplink radio resourceconfiguration. In FIG. 10, the horizontal axis represents time, and thevertical axis represents frequency. FIG. 10 shows the configuration of asingle radio frame, which is divided into a plurality of resourceblocks. In FIG. 10, resource blocks are configured in units of regionseach circumscribed with 1.25 MHz frequency-width and 1 ms time-width, sothat the random access channel (RACH), the uplink shared channel(PUSCH), and the uplink control channel (PUCCH) illustrated in FIG. 9are assigned to these regions.

That is, the random access channels (RACH) are assigned to resourceblocks illustrated as dot-hatching regions; the uplink shared channels(PUSCH) are assigned to resource blocks illustrated as blank regions;and the uplink control channels (PUCCH) are assigned to resource blocksillustrated as horizontal-line-hatching regions.

The random access channel (RACH) for the uplink of EUTRA includesasynchronous random access channels and synchronous random accesschannels. The asynchronous random access channel uses a minimum unit ata 1.25 MHz band. The base station device employs a plurality of randomaccess channels to cope with accesses from numerous mobile stationdevices. The maximum object of using the asynchronous random accesschannel is to establish synchronization between the mobile stationdevice and the base station device. The random access channel plays anadditional role for issuing a scheduling request which is used by themobile station device requesting a new uplink resource due to a shortageof assignment of resources (see Non-Patent Document 2).

Asynchronous random access includes two accesses, namely, a contendedrandom access (or a contention-based random access) and a non-contendedrandom access (or a non-contention-based random access).

The contended random access is a normally processed random access likelycausing the contention between mobile station devices.

The non-contended random access is a random access causing no contentionbetween base station devices, which is processed under the initiative ofthe base station device in case of handover or the like for rapidlyestablishing synchronization between the base station device and themobile station device.

In asynchronous random access, the mobile station device transmits apreamble for establishing synchronization with the base station device.This is called a random access preamble. This preamble includessignatures, i.e. signal patterns representative of the information. Adesired signature is selected from among several tens of presetsignatures so as to designate the information consisting of severalbits.

In recent EUTRA, the mobile station device transmits 6-bit informationto the base station device by way of the signature. The 6-bittransmission needs sixty-four types of preambles, i.e. 2 to the 6thpower. The 6-bit information is referred to as a preamble ID. In the6-bit preamble ID, a random ID is assigned to five bits, while theinformation representing the amount of information needed for a randomaccess request is assigned to the remaining one bit (see Non-PatentDocument 3).

FIG. 11 is a sequence diagram showing a contended random access processfor asynchronous random access. First, the mobile station device selectsa signature based on various pieces of information such as the random IDand the downlink path-loss/CQI (Channel Quality Indicator), thustransmitting an random access preamble as a message M1 via anasynchronous random access channel (step S01).

Upon reception of the random access preamble from the mobile stationdevice, the base station device calculates a synchronous timingdeviation occurring between the mobile station device and the basestation device on the basis of the random access preamble, thus,producing the synchronous timing deviation information; it performsscheduling to transmit an L2/L3 (Layer 2/Layer 3) message, thusproducing the scheduling information; then, it assigns the temporaryintra-cell identification information of the mobile station device (orT-C-RNTI: Temporary Cell-Radio Network Temporary Identity) to the mobilestation device.

The base station device sets RA-RNTI (Random Access-Radio NetworkTemporary Identity), representing that a random access response to themobile station device transmitting the random access preamble via therandom access channel is set to the downlink shared channel (PDSCH), tothe downlink control channel (PDCCH).

With the resource block for the downlink shared channel (PDSCH)notifying the allocation of the random access response via the RA-RNTI,the base station device transmits a message M2 representative of therandom access response including the synchronous timing deviationinformation, the scheduling information, the T-C-RNTI and the receivedpreamble ID number (or the random ID) to the base station device (stepS02).

The RA-RNTI indicates a specific value which is not used as the C-RNTI(Cell-Radio Network Temporary Identity), so that the mobile stationdevice detects the specific value to identify setting the random accessresponse to the downlink shared channel (PDSCH).

FIG. 12 shows an example of allocation of the random access response tothe downlink shared channel (PDSCH) when notifying the mobile stationdevice of the allocation via the RA-RNTI. As illustrated in FIG. 11, inwhich the allocation of the random access response is notified using theRA-RNTI, the random access response including the synchronous timingdeviation information, the scheduling information, the T-C-RNTI and thesignature ID number of the received preamble are stored in a singleresource block of the downlink shared channel (PDSCH) with respect to aplurality of mobile station devices (i.e. n devices where n is aninteger of two or more in FIG. 12).

In FIG. 11, when the mobile station device identifies that the RA-RNTIis set to the downlink control channel (PDCCH) of the message M2, itassesses the content of the random access response set to the downlinkshared channel (PDSCH) so as to extract the response including thesignature ID number (or the random ID) of the transmitted preamble, thuscorrecting the synchronous timing deviation based on the synchronoustiming deviation information within the response.

Based on the received scheduling information, the mobile station devicetransmits a message M3 representative of the L2/L3 message including atleast the C-RNTI (or the core network ID such as the TMSI (TemporaryMobile Subscriber Identity)) in the scheduled resource block to the basestation device (step S03).

Upon reception of the L2/L3 message from the mobile station device, thebase station device refers to the C-RNTI (or the core network ID such asTMSI) included in the received L2/L3 message so as to transmit a messageM4 representative of a contention resolution identifying the contentionoccurring between mobile station devices to the mobile station device(step S04). The procedures of steps S01 to S04 are described inNon-Patent Document 3.

FIG. 13 is a sequence diagram showing a transmission process of downlinkdata from the base station device to the mobile station device accordingto the conventional technology. The process of FIG. 13 uses HARQ (HybridAutomatic Repeat Request).

In the process of HARQ, the base station device transmits downlinkcontrol data to the mobile station device via the downlink controlchannel (PDCCH) (step S11).

Then, the mobile station device makes a decision whether or not todetect the downlink control data being transmitted in step S11 (stepS12).

The base station device transmits downlink transmission data to themobile station device via the downlink shared channel (PDSCH) (stepS13).

Then, the mobile station device makes a decision whether or not todetect the downlink transmission data being transmitted in step S13(step S14).

After decoding the data transmitted in step S11 and in step S13, themobile station device feeds back ACK (Positive Acknowledgement) in thecase of a success of CRC (Cyclic Redundancy Check) or NACK (NegativeAcknowledgement) in the case of a failure of CRC to the base stationdevice (step S15), thus making a determination whether or not to repeattransmission.

Just after reception of data via the downlink shared channel (PDSCH) instep S13, the ACK/NACK is transmitted via the uplink shared controlchannel (PUCCH).

Non-Patent Document 1: 3GPP TS (Technical Specification) 36.211, V1.10(2007-05), Technical Specification Group Radio Access Network, PhysicalChannel and Modulation (Release 8)

Non-Patent Document 2: 3GPP TS (Technical Specification) 36.212, V1.20(2007-05), Technical Specification Group Radio Access Network,Multiplexing and Channel Coding (Release 8)

-   -   Non-Patent Document 3: R2-072338 “Update on Mobility, Security,        Random Access Procedure, etc.” 3GPP TSG RAN WG2 Meeting #58        Kobe, Japan, 7-11 May, 2007

DISCLOSURE OF INVENTION Problem to be Solved by the Invention

In the UETRA, the mobile station device processing the contended randomaccess according to the asynchronous random access needs to detect therandom access response (message M2) by monitoring the RA-RNTI. In thecase of the random access processed due to an uplink resource request,uplink synchronization of the mobile station device is maintained.Uplink synchronization is the most important factor in asynchronousrandom access but is not necessarily processed due to an uplink resourcerequest. That is, the mobile station device is capable of performinguplink transmission on a feedback signal of HARQ in downlinkcommunication, which will be thus continued.

When the mobile station device issuing an uplink resource requestperforms timing alignment (or synchronous deviation correction) based onthe timing deviation information included in the random access response,the uplink synchronous/asynchronous state managed by the mobile stationdevice may be inconsistent with the synchronous/asynchronous statemanaged by the base station device, thus causing a problem in needlesslytriggering an error recovery process.

When the mobile station device issuing an uplink resource requestmonitors only the RA-RNTI in the random access response, it mayerroneously ignore a downlink resource assignment notified by theC-RNTI. In this case, the mobile station device suffers from a problemin degrading the quality of downlink data communication due to theissuance of an uplink resource request.

In addition, when the base station device processes an uplink resourceassignment by some triggering, if the mobile station device monitorsonly the RA-RNTI in the random access response, it may erroneouslyignore the uplink resource assignment notified by the C-RNTI. In thiscase, the mobile station device suffers from a problem in failing todetect the uplink resource request being needlessly continued.

The present invention is created in light of the aforementionedcircumstances, and an object thereof is to provide a mobile stationdevice and a radio communication system capable of implementing highlyefficient communications between mobile station devices and base stationdevices.

Means for Solving the Problems

-   (1) The present invention is made to solve the above problems,    wherein according to one embodiment of the present invention, a    radio communication system is constituted of a mobile station device    which transmits a random access preamble to a base station device    and performs uplink timing alignment based on synchronization timing    deviation information included in a random access response which the    base station device transmits in response to the transmitted random    access preamble, and the base station device which receives the    random access preamble from the mobile station device and transmits    a random access response including synchronization deviation    information calculated based on the reception timing of the random    access preamble to the mobile station device, wherein, in an uplink    synchronous status, the mobile station device does not perform    uplink timing alignment based on synchronization timing deviation    information included in a random access response, which is a    response to a random access preamble whose preamble ID is randomly    selected by the mobile station device.-   (2) The uplink synchronous status is managed by a timer, so that the    uplink synchronous status is sustained until the timer expires.-   (3) According to one embodiment of the present invention, the mobile    station device transmits a random access preamble to a base station    device and performs uplink timing alignment based on the    synchronization timing deviation information included in a random    access response which the base station device transmits in response    to the transmitted random access preamble, wherein, in an uplink    synchronous status, the mobile station device does not perform    uplink timing alignment based on synchronization timing deviation    information included in a random access response which is a response    to a random access preamble whose preamble ID is randomly selected    by the mobile station device.-   (4) The uplink synchronous status is managed by a timer, so that the    uplink synchronous status is sustained until the timer expires.-   (5) According to one embodiment of the present invention, a radio    communication system is constituted of a mobile station device which    transmits a random access preamble to a base station device and    resets a timer managing an uplink synchronous status based on the    synchronization timing deviation information included in a random    access response which the base station device transmits in response    to the transmitted random access preamble, and the base station    device which receives the random access preamble from the mobile    station device and transmits a random access response including    synchronization timing deviation information calculated based on the    reception timing of the random access preamble, wherein, in an    uplink synchronous status, the mobile station device does not    perform to reset the timer based on the reception of synchronization    timing deviation information included in a random access response    that is a response to a random access preamble whose preamble ID is    randomly selected by the mobile station device.-   (6) The uplink synchronous status is sustained until the timer    expires.-   (7) According to one embodiment of the present invention, a mobile    station device transmits a random access preamble to a base station    device and resets a timer managing an uplink synchronous status    based on reception of the synchronization timing deviation    information included in a random access response that the base    station device transmits in response to the transmitted random    access preamble, wherein, in the uplink synchronous status, the    mobile station device does not perform to reset the timer based on    reception of synchronization timing deviation information included    in a random access response which is a response to a random access    preamble whose preamble ID is randomly selected by the mobile    station device.-   (8) The uplink synchronous status is sustained until the timer    expires.-   (9) According to one embodiment of the present invention, a radio    communication system is constituted of a mobile station device which    transmits a random access preamble to a base station device and    transmits uplink data based on an uplink resource assignment    notified by way of a random access response indicated by an RA-RNTI    which the base station device transmits in response to the    transmitted random access preamble, and the base station device    which receives the random access preamble from the mobile station    device and transmits, to the mobile station device, the RA-RNTI    indicating the random access response notifying an uplink resource    assignment in response to the received random access preamble to the    mobile station device, wherein the mobile station device monitors    both a C-RNTI notifying the uplink resource assignment from the base    station device at an arbitrary timing and the RA-RNTI, thus    transmitting uplink data.-   (10) According to one embodiment of the present invention, a mobile    station device transmits a random access preamble to a base station    device and transmits uplink data based on an uplink resource    assignment notified by way of a random access response indicated by    an RA-RNTI which the base station device transmits in response to    the transmitted random access preamble, wherein the mobile station    device monitors both a C-RNTI notifying an uplink resource    assignment from the base station device at an arbitrary timing and    the RA-RNTI, thus transmitting uplink data.-   (11) According to one embodiment of the present invention, a radio    communication system is constituted of a mobile station device which    transmits a random access preamble to a base station device and    receives a random access response which the base station device    transmits in response to the transmitted random access preamble, and    the base station device which receives the random access preamble    from the mobile station device and transmits a random access    response in response to the received random access preamble, wherein    the mobile station device concurrently receives downlink data which    the base station device transmits at an arbitrary timing and the    random access response.-   (12) According to one embodiment of the present invention, a radio    communication system is constituted of a mobile station device which    transmits a random access preamble to a base station device and    receives a random access response based on an RA-RNTI which the base    station device transmits in response to the transmitted random    access preamble, and the base station device which receives the    random access preamble from the mobile station device and transmits,    to the mobile station device, the RA-RNTI notifying a resource    assignment of the random access response in response to the received    random access preamble, wherein the mobile station device monitors    both a C-RNTI notifying a downlink resource assignment from the base    station device at an arbitrary timing and the RA-RNTI, thus    receiving both the random access response and downlink data or    either the random access response or the downlink data.-   (13) According to one embodiment of the present invention, a mobile    station device transmits a random access preamble to a base station    device and receives a random access response which the base station    device transmits in response to the transmitted random access    preamble, wherein the mobile station device concurrently receives    the random access response and downlink data which the base station    device transmits at an arbitrary timing.-   (14) According to one embodiment of the present invention, a mobile    station device transmits a random access preamble to a base station    device and receives a random access response based on an RA-RNTI    which the base station device transmits in response to the    transmitted random access preamble, wherein the mobile station    device monitors both a C-RNTI notifying a downlink resource    assignment from the base station device at an arbitrary timing and    the RA-RNTI, thus receiving both the random access response and    downlink data or either the random access response or the downlink    data.

EFFECT OF THE INVENTION

According to the present invention, it is possible to perform highlyefficient communication between a mobile station device and a basestation device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram showing the constitution of a basestation device 10 according to an embodiment of the present invention.

FIG. 2 is a schematic block diagram showing the constitution of a mobilestation device 50 according to the embodiment of the present invention.

FIG. 3 is a schematic block diagram showing the constitution of acontrol data extraction unit 56 of the mobile station device 50 (FIG. 2)according to the embodiment of the present invention.

FIG. 4 is a sequence diagram showing the processing of a radiocommunication system according to the embodiment of the presentinvention.

FIG. 5 is a sequence diagram showing the processing of the radiocommunication system according to the embodiment of the presentinvention.

FIG. 6 is a flowchart showing the processing of the base station device10 according to the embodiment of the present invention.

FIG. 7 is a flowchart showing the processing of the mobile stationdevice 50 according to the embodiment of the present invention.

FIG. 8 is a sequence diagram showing the processing of a radiocommunication system according to a variation of the embodiment of thepresent invention.

FIG. 9 is an illustration showing uplink and downlink channelconfigurations for EUTRA.

FIG. 10 is a chart showing an example of an uplink radio resourceconfiguration.

FIG. 11 is a sequence diagram showing a contended random access processfor an asynchronous random access.

FIG. 12 is an example of allocation of a random access response to adownlink shared channel (PDSCH) when notifying the mobile station deviceof an allocation of RA-RNTI.

FIG. 13 is a sequence diagram showing a transmission process of downlinkdata from the base station device to the mobile station device accordingto the conventional technology.

REFERENCE SYMBOLS

10 . . . base station device, 11 . . . data control unit, 12 . . . OFDMmodulation unit, 13 . . . scheduling unit, 14 . . . channel estimationunit, 15 . . . DFT-S-OFDM demodulation unit, 16 . . . control dataextraction unit, 17 . . . preamble detection unit, 18 . . . radio unit,21 . . . DL scheduling unit, 22 . . . UL scheduling unit, 23 . . .message generation unit, 31 . . . C-RNTI detection unit, 32 . . .RA-RNTI detection unit, 33 . . . C-RNTI/RA-RNTI detection unit, 34 . . .detection switchover unit, 35 . . . extraction unit, 50 . . . mobilestation device, 51 . . . data control unit, 52 . . . DFT-S-OFDMmodulation unit, 53 . . . scheduling unit, 54 . . . OFDM demodulationunit, 55 . . . channel estimation unit, 56 . . . control data extractionunit, 57 . . . synchronization correction unit, 58 . . . preamblegeneration unit, 59 . . . preamble selection unit, 60 . . . radio unit,531 . . . ACK/NACK transmission control unit, A1 . . . antenna, A2 . . .antenna.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be describedwith reference to drawings. Similar to the EUTRA achieving the evolutionof the third-generation radio access, the radio communication system ofthe present embodiment is constituted of a base station device and aplurality of mobile station devices. In the present embodiment, thecommunication link directed from the mobile station device to the basestation device is referred to as an uplink, and the communication linkdirected from the base station device to the mobile station device isreferred to as a downlink.

The downlink of the present embodiment is constituted of a downlinkpilot channel (DPiCH), a downlink synchronization channel (DSCH), adownlink shared channel (PDSCH), a downlink control channel (PDCCH), anda common control channel (CCPCH).

The uplink of the present embodiment is constituted of an uplink pilotchannel (UPiCH), a random access channel (RACH), an uplink sharedchannel (PUSCH), and an uplink control channel (PUCCH).

Similar to the foregoing one, radio resources of the present embodimentare divided into resource blocks corresponding to regions eachcircumscribed with 1.25 MHz frequency-width and 1 ms time-width. Thebase station device performs scheduling to assign resource blocks tomobile station devices, thus achieving radio communications with mobilestation devices.

The present embodiment employs OFDMA (Orthogonal Frequency DivisionMultiple Access) as the downlink communication method and DFT-S-OFDM asthe uplink communication method, so that resource blocks (blocks) areregions dividing radio resources in frequency and time directions,whereas in case of the communication method of TDMA (Time DivisionMultiple Access), resource blocks are regions dividing radio resourcesin the time direction. In the case of the communication method of FDMA(Frequency Division Multiple Access), resource blocks are regionsdividing radio resources in the frequency direction. In the case of thecommunication method of CDMA (Code Division Multiple Access), resourceblocks are regions dividing radio resources with spread codes.

The random access channel (RACH) of the present embodiment is used foran asynchronous mobile station device to synchronize the mobile stationdevice with the base station device. It is also used for a synchronizingmobile station device to issue a scheduling request (an uplink resourcerequest) via the random access channel (RACH). The random access channel(RACH) is a channel having a guard time (e.g. 97 micro seconds) and is achannel which is available for a non-synchronizing mobile stationperforming transmission. Upon reception of a random access preamble(e.g. a preamble length of 0.8 ms) from the mobile station device, thebase station device detects deviation of the arrival time of thepreamble with respect to a reference time, thus generating timingdeviation information. The precision of the timing deviation informationis 0.52 micro seconds, for example.

The asynchronous random access is divided into two types of accesses,i.e. contended random access and non-contended random access. Thecontended random access is a random access in which a contention likelyoccurs between mobile station devices because the mobile station devicedetermines a preamble ID number so as to send it to the base stationdevice.

The non-contended random access is a random access in which nocontention occurs between mobile station devices because the mobilestation device transmits the preamble ID number designated by the basestation device. The preamble ID number used for the contended randomaccess is notified in advance and is not used for the non-contendedrandom access. Therefore, it is possible to discriminate between thecontended random access and the non-contended random access withreference to the preamble ID number.

FIG. 1 is a schematic block diagram showing the constitution of a basestation device 10 according to the embodiment of the present invention.

The base station device 10 includes a data control unit 11 (referred toas a response control data transmission unit, a downlink control datatransmission unit, or a downlink control channel transmission unit), anOFDM modulation unit 12, a scheduling unit 13, a channel estimation unit14, a DFT-S-OFDM (DFT-spread OFDM) demodulation unit 15, a control dataextraction unit 16, a preamble detection unit 17 (referred to as apreamble reception unit), a radio unit 18, and an antenna A1. A basestation communication unit 19 is constituted of the data control unit11, the OFDM modulation unit 12, the scheduling unit 13, the channelestimation unit 14, the DFT-S-OFDM demodulation unit 15, the controldata extraction unit 16, the preamble detection unit 17, the radio unit18, and the antenna A1.

A transmission unit 20 is constituted of the data control unit 11, theOFDM modulation unit 12, the radio unit 18, and the antenna A1, whilethe reception unit 21 is constituted of the channel estimation unit 14,the DFT-S-OFDM demodulation unit 15, the control data extraction unit16, the preamble detection unit 17, the radio unit 18, and the antennaA1.

With respect to control data and user data (including random accessresponses and preamble assignment information) given by an upper layer(not shown), the data control unit 11, in accordance with instructionsgiven by the scheduling unit 13, performs mapping control data onto thedownlink pilot channel (DPiCH), the downlink synchronization channel(DSCH), the downlink control channel (PDCCH), and the common controlchannel (CCPCH), and performs mapping user data for each mobile stationdevice and control data for a MAC layer (Medium Access Control: Layer 2)or a higher layer onto the downlink shared channel (PDSCH), thusoutputting mapping data to the OFDM modulation unit 12.

The OFDM modulation unit 12 performs a variety of OFDM signal processingsuch as data modulation, series/parallel conversion, IFFT (Inverse FastFourier Transform), CP (Cyclic Prefix) insertion, and filtering on userdata and control data subjected to mapping with respect to each channel,thus generating and outputting OFDM signals to the radio unit 18.

The radio unit 18 performs up-conversion on OFDM signals outputted fromthe OFDM modulation unit 12 into the radio frequencies, thustransmitting them to the mobile station device via the antenna A1.

The radio unit 18 receives uplink signals from the mobile station devicevia the antenna A1, wherein received signals are subjected todown-conversion into baseband signals, which are then forwarded to theDFT-S-OFDM demodulation unit 15, the channel estimation unit 14, and thepreamble detection unit 17.

The channel estimation unit 14 estimates characteristics of a radiopropagation path with respect to the uplink pilot channel (UPiCH) basedon baseband signals outputted from the radio unit 18, thus outputting anestimation result of the radio propagation path to the DFT-S-OFDMdemodulation unit 15. The channel estimation unit 14 outputs theestimation result of the radio propagation path to the scheduling unit13 so as to perform uplink scheduling with respect to the uplink pilotchannel (UPiCH) of the radio unit 18.

In accordance with the estimation result of the radio propagation pathand an instruction of the control data extraction unit 16, theDFT-S-OFDM demodulation unit 15 performs DFT-spread-OFDM demodulation onbaseband signals outputted from the radio unit 18, thus generating andoutputting reception data to the control data extraction unit 16.

As the uplink communication method, the present embodiment uses either asingle carrier method of DFT-spread-OFDM or a multicarrier method ofOFDM.

The control data extraction unit 16 performs true-false discriminationon reception data outputted from the DFT-S-OFDM demodulation unit 15,thus outputting the discrimination result to the scheduling unit 13.When reception data is true, the control data extraction unit 16 dividesreception data into user data and control data.

The control data extraction unit 16 outputs, to the scheduling unit 13,control data representing the downlink CQI information, ACK/NACK ofdownlink data, and Layer 2 regarding a resource assignment request,while it outputs, to an upper layer (not shown) of the base stationdevice 10, control data regarding the Layer 3 or the like and user data.

When reception data is false, the control data extraction unit 16preserves reception data to be mixed with retransmission data and then,it performs mixing upon reception of retransmission data.

The preamble detection unit 17 detects a preamble from baseband signalsoutputted from the radio unit 18 and then calculates a synchronizationtiming deviation based on the preamble, thus outputting thesynchronization timing deviation to the scheduling unit 13 together withthe preamble ID number denoted by the preamble.

The scheduling unit 13 includes a DL (Down Link) scheduling unit 21implementing downlink scheduling and a UL (Up Link) scheduling unit 22implementing uplink scheduling, and a message generation unit 23.

The DL scheduling unit 21 performs scheduling for mapping user data ontodownlink channels on the basis of the CQI information notified by themobile station device and the user data information notified by theupper layer as well as control data generated by the message generationunit 23.

In accordance with the estimation result of an uplink radio propagationpath outputted from the channel estimation unit 14 and the resourceassignment request of the mobile station device outputted from thecontrol data extraction unit 16, the UL scheduling unit 22 performsscheduling for mapping user data onto uplink channels.

The message generation unit 23 generates the downlink resourceassignment information, the uplink resource assignment, ACK/NACK ofuplink data, and control data such as random access responses. Themessage generation unit 23 stores, in the random access responsemessage, the preamble ID number and the synchronization timing deviationinformation representing the synchronization timing deviation outputtedfrom the preamble detection unit 17 when generating the random accessresponse message.

FIG. 2 is a schematic block diagram showing the constitution of themobile station device 50 according to the embodiment of the presentinvention.

The base station device 50 includes a data control unit 51 (referred toas a preamble transmission unit), a DFT-S-OFDM modulation unit 52, ascheduling unit 53, an OFDM demodulation unit 54, a channel estimationunit 55, a control data extraction unit 56 (referred to as a judgmentunit or a downlink control channel reception unit), a synchronizationcorrection unit 57, a preamble generation unit 58, a preamble selectionunit 59, a radio unit 60, and an antenna A2. A mobile stationcommunication unit 61 is constituted of the data control unit 51, theDFT-S-OFDM modulation unit 52, the scheduling unit 53, the OFDMdemodulation unit 54, the channel estimation unit 55, the control dataextraction unit 56, the synchronization correction unit 57, the preamblegeneration unit 58, the preamble selection unit 59, the radio unit 60,and the antenna A2.

A transmission unit 62 is constituted of the data control unit 51, theDFT-S-OFDM modulation unit 52, the synchronization correction unit 57,the preamble generation unit 58, the preamble selection unit 59, theradio unit 60, and the antenna A2. A reception unit 63 is constituted ofthe OFDM demodulation unit 54, the channel estimation unit 55, thecontrol data extraction unit 56, the radio unit 60, and the antenna A2.

In accordance with instructions given by the scheduling unit 53, thedata control unit 51 allocates control data (including preambles andACK/NACK) and user data given by an upper layer (not shown) of themobile station device 50 so as to transmit them to the base stationdevice via the random access channel (RACH), the uplink shared channel(PUSCH), and the uplink control channel (PUCCH).

In this connection, the data control unit 51 sets the random accesschannel (RACH) with respect to a preamble while setting the uplinkcontrol channel (PUCCH) with respect to ACK/NACK. In addition, the datacontrol unit 51 sets the uplink pilot channel (UPiCH).

The DFT-S-OFDM modulation unit 52 performs a variety of DFT-S-OFDMsignal processing such as data modulation, DFT conversion, sub-carriermapping, IFFT, CP insertion, and filtering on user data and control dataallocated to channels, thus generating and outputting DFT-Spread-OFDMsignals to the synchronization correction unit 57.

Based on the synchronization timing deviation information outputted fromthe control data extraction unit 56, the synchronization correction unit57 corrects the transmission timing with respect to DFT-Spread-OFDMoutputted from the DFT-S-OFDM modulation unit 52, thus outputting themto the radio unit 60.

Upon setting radio frequencies designated by a radio control unit (notshown), the radio unit 60 performs up-conversion on DFT-Spread-OFDMsignals outputted from the synchronization correction unit 57 into theradio frequencies, thus transmitting them to the base station device viathe antenna A2.

Upon reception of downlink signals from the base station device via theantenna A2, the radio unit 60 performs down-conversion on receivedsignals into baseband signals, thus outputting them to the OFDMdemodulation unit 54 and the channel estimation unit 55.

The channel estimation unit 55 estimates characteristics of a radiopropagation path with reference to the downlink pilot channel (DPiCH)included in baseband signals outputted from the radio unit 60, thusoutputting the estimation result to the OFDM demodulation unit 54. Thechannel estimation unit 55 converts the estimation result into CQIinformation so as to transmit the estimation result of the radiopropagation path to the base station device, thus outputting the CQIinformation to the scheduling unit 53.

With reference to the estimation result of the radio propagation pathoutputted from the channel estimation unit 55, the OFDM demodulationunit 54 demodulates baseband signals outputted from the radio unit 60into reception data, thus outputting them to the control data extractionunit 56.

The control data extraction unit 56 divides reception data outputtedfrom the OFDM demodulation unit 54 into user data and control data. Thecontrol data extraction unit 56 outputs the synchronization timingdeviation information of control data to the synchronization correctionunit 57, outputs the scheduling information and other Layer 2 controldata to the scheduling unit 53, and outputs user data and Layer 3control data to the upper layer (not shown) of the mobile station device50.

In accordance with the scheduling information outputted from the upperlayer of the mobile station device 50 and the control data of the basestation device outputted from the control data extraction unit 56, thescheduling unit 53 instructs the data control unit 51 to perform mappingthe control information and data onto channels.

When making random access to the base station device, the schedulingunit 53 instructs the preamble selection unit 59 to make random accessupon selecting the preamble ID number and instructs the reception methodfor the control data extraction unit 56.

The scheduling unit 53 manages the uplink synchronous/asynchronousstatus and manages either the uplink synchronous status or the uplinkasynchronous status when making random access to the base stationdevice, thus instructing the reception method for the control dataextraction unit 56.

When instructing the reception method for the control data extractionunit 56, the scheduling unit 53 instructs the control data extractionunit 56 to monitor the C-RNTI for use in reception of downlink data andtransmission of uplink data and the RA-RNTI and to receive a randomaccess response message, in case of processing an uplink resourcerequest.

When making random access irrelevant to the uplink resource request (orwhen making random access in the uplink asynchronous status), itinstructs the control data extraction unit 56 to monitor the RA-RNTI andto receive the random access response message. When receiving downlinkdata or when transmitting uplink data, it instructs the control dataextraction unit 56 to monitor the C-RNTI. Downlink control data for usein reception of downlink data and an uplink grant for use intransmission of uplink data are set to the downlink control channel(PDCCH) with different formats, whereas the same C-RNTI is used for theidentification information of the mobile station device. When makingrandom access relevant to the uplink resource request (or when makingrandom access in the uplink synchronous status), it instructs thecontrol data extraction unit 56 to monitor both the C-RNTI and theRA-RNTI.

The scheduling unit 53 is equipped with an ACK/NACK transmission controlunit 531. The ACK/NACK transmission control unit 531 rectifies thetransmission method for ACK/NACK based on the transmission timing of themessage M3 and the result of CRC detected by the control data extractionunit 56.

The scheduling unit 53 instructs the preamble selection unit 59 toselect the preamble ID number used for random access, thus outputtingthe selected preamble ID number to the preamble generation unit 58.

The preamble generation unit 58 generates the preamble based on thepreamble ID number selected by the preamble selection unit 59, thusoutputting it to the DFT-S-OFDM modulation unit 52.

FIG. 3 is a schematic block diagram showing the constitution of thecontrol data extraction unit 56 of the mobile station device 50 (FIG. 2)according to the embodiment of the present invention. The control dataextraction unit 56 includes a C-RNTI detection unit 31, a RA-RNTIdetection unit 32, a C-RNTI/RA-RNTI detection unit 33, a detectionswitchover unit 34, and an extraction unit 35.

The C-RNTI detection unit 31 detects the C-RNTI assigned to the mobilestation itself from the downlink control channel (PDCCH) outputted fromthe OFDM demodulation unit 54 (FIG. 2) so as to extract the controlinformation pertaining to the C-RNTI from the downlink control channel(PDCCH) and to analyze the control information, thus identifying eitherthe downlink shared channel (PDSCH) or the uplink shared channel (PUSCH)being assigned to the mobile station itself. The C-RNTI detection unit31 outputs the analysis result to the extraction unit 35.

The RA-RNTI detection unit 32 detects the RA-RNTI from the downlinkcontrol channel (PDCCH) outputted from the OFDM demodulation unit 54(FIG. 2) so as to extract the control information pertaining to theRA-RNTI from the downlink control channel (PDCCH) and to analyze thecontrol information, thus identifying the downlink shared channel(PDSCH) assigned to the random access response. The RA-RNTI detectionunit 32 outputs the analysis result to the extraction unit 35.

The C-RNTI/RA-RNTI detection unit 33 detects either the C-RNTI or theRA-RNTI being assigned to the mobile station itself from the downlinkcontrol channel (PDCCH) outputted from the OFDM demodulation unit 54(FIG. 2) so as to extract the control information pertaining to theC-RNTI or the RA-RNTI from the downlink control channel (PDCCH) and toanalyze the control information, thus outputting the analysis result tothe extraction unit 35.

The scheduling unit 53 instructs the detection switchover unit 34 toswitch over the C-RNTI detection unit 31, the RA-RNTI detection unit 32,and the C-RNTI/RA-RNTI detection unit 33, thus forwarding any one of theoutput data to the extraction unit 35.

Based on the analysis result of the control information corresponding toany one of the output data of the C-RNTI detection unit 31, the RA-RNTIdetection unit 32, and the C-RNTI/RA-RNTI detection unit 33, theextraction unit 35 extracts data (including the random access responsemessage) from the downlink shared channel (PDSCH) assigned to the mobilestation device itself.

Upon extraction of the random access response from the downlink sharedchannel (PDSCH), it outputs control data including the random accessresponse message (such as the synchronization timing deviationinformation) to the scheduling unit 35 (FIG. 2) and the synchronizationcorrection unit 57 (FIG. 2) while outputting user data to the upperlayer (not shown) of the mobile station device 50.

Upon extraction of downlink data from the downlink shared channel(PDSCH), it outputs control data including the CRC result to thescheduling unit 35 while outputting user data to the upper layer (notshown) of the mobile station device 50.

The mobile station device and the base station device manage the uplinksynchronous/asynchronous status of the mobile station device by use of atimer. The base station device transmits the synchronization timingdeviation information to the mobile station device by way of the randomaccess response or a timing alignment command message. The base stationdevice resets the timer when transmitting the synchronization timingdeviation information or the mobile station device resets the timer whenreceiving the synchronization timing deviation information. The basestation device notifies the mobile station device of an expiration valueof the timer by way of a broadcast signal or a dedicated signal. Thebase station device and the mobile station device manage the uplinksynchronous/asynchronous status as the uplink synchronous status untilthe expiration of the timer.

The base station device and the mobile station device manage the uplinksynchronous/asynchronous status as the uplink asynchronous status afterthe expiration of the timer. The timing alignment command message isgenerated by the base station upon detection of a synchronization timingdeviation occurring in the uplink transmission (using normal data,uplink pilot channels, etc) from the mobile station device.

FIG. 4 is a sequence diagram showing a processing of the radiocommunication system according to the embodiment of the presentinvention.

The sequence diagram of FIG. 4 shows the processing regarding an uplinkresource request by way of a contended random access. This shows theprocessing for issuing the uplink resource request due to the occurrenceof data to be transmitted in the mobile station device in the uplinkasynchronous status. The mobile station device transmits a preamble of apreamble ID number, which is randomly selected from among preamble IDsavailable for the contended random access, to the base station device(step S101).

The base station device detects the above preamble transmitted theretofrom the mobile station device. Herein, the preamble is a signal patternsuited to the preamble ID number, wherein the base station devicedetects the preamble upon detecting a reception signal matching thesignal pattern of the preamble ID number.

The random access response, which is illustrated in step S02 of FIG. 1and which is transmitted to the mobile station device from the basestation device, is constituted of random access response control data(step S102) being transmitted via the downlink control channel (PDCCH)and random access response data (step S103) being transmitted via thedownlink shared channel (PDSCH).

The base station device transmits random access response control dataincluding the RA-RNTI and the resource assignment information to themobile station device via the downlink control channel (PDCCH) (stepS102), thus designating a resource block (PDSCH) for allocating therandom access response data.

In addition, the base station device transmits random access responsedata in the resource block designated by the random access responsecontrol data (step S103).

After completion of transmission of the preamble to the base stationdevice, the mobile station device receives the random access responsecontrol data and random access response data from the base stationdevice (steps S102, S103). The mobile station device receives a randomaccess response message for the preamble previously transmitted byitself by way of acquisition of the message whose preamble ID numberwhich is included in the random access response data matches thepreamble ID number of the preamble previously transmitted by itself. Themobile station device aligns the uplink timing (or uplinksynchronization processing) and resets the timer on the basis of thesynchronization timing deviation information included in the randomaccess response message.

The mobile station device transmits the L2/L3 message (random accessinformation) (message M3) including the C-RNTI to the base stationdevice in the resource designated by the scheduling information includedin the random access response message (step S104). The random accessinformation includes the information representative of the uplinkresource request and an uplink buffer status representative of theamount of uplink data stored in an uplink buffer.

The base station device transmits an uplink grant responsive to theuplink resource request to the mobile station device via the downlinkcontrol channel (PDCCH) (step S105). The mobile station device receivingthe uplink grant transmits uplink data to the base station device viathe uplink shared channel (PUSCH) (step S106).

FIG. 5 is a sequence diagram showing a processing of the radiocommunication system according to the embodiment of the presentinvention.

FIG. 5 shows the concurrent execution of the random access processingand the downlink data communication processing. This shows theprocessing for issuing an uplink resource request due to the occurrenceof data which should be transmitted in the mobile station device in theuplink synchronization status. First, the transmission unit 62 of themobile station device transmits the preamble including the preamble IDnumber via the random access channel, thus transmitting the uplinkresource request (step S201).

The reception unit 21 of the base station device 10 receives the abovepreamble from the mobile station device 50. The reception unit 21receiving the preamble transmits the random access response control datato the mobile station device 50. That is, the transmission unit 20transmits the random access response control data including the RA-RNTIinformation and the resource assignment for the random access responsedata to the mobile station device 50 via the downlink control channel(PDCCH) (step S202). The reception unit 63 of the mobile station device50 receives the data which the base station device 10 transmits via thedownlink control channel (PDCCH) in step S202. The control dataextraction unit 56 makes a decision as to whether or not the RA-RNTI isincluded in the downlink control channel (PDCCH) received by thereception unit 63 in step S202, wherein it makes a decision as towhether or not it is the response control data which is transmitted bythe base station device 10 in response to the preamble transmitted bythe transmission unit 62.

Next, the transmission unit 20 of the base station device 10 transmitsthe random access response data including the preamble ID, the T-C-RNTI,the synchronization deviation information, and the schedulinginformation for the message M3 to the mobile station device 50 via thedownlink shared channel (PDSCH) (step S203).

Then, the control data extraction unit 56 of the mobile station device50 performs cyclic redundancy checking (CRC) on the reception data ofthe reception unit 63 in step S203, wherein it receives the randomaccess response message for the preamble previously transmitted byitself by way of acquisition of the message whose preamble ID numberwhich is included in the random access response data matches thepreamble ID number previously transmitted by itself.

The base station device 10 transmits the downlink data to the mobilestation device in parallel with the random access response (steps S204,S205). The transmission unit 20 of the base station device 10 transmitsthe downlink control data including the resource assignment and theC-RNTI information to the mobile station device 50 via the downlinkcontrol channel (PDCCH) (step S204). The reception unit 63 of the mobilestation device 50 receives the downlink control data transmitted theretofrom the base station device 10.

The control data extraction unit 56 of the mobile station device 50makes a decision as to whether or not the C-RNTI for the mobile stationdevice itself is included in the reception data of the reception unit 63in step S204, wherein when the C-RNTI for the mobile station deviceitself is included, it recognizes the resource position and themodulation method with respect to the subsequent downlink shared channel(PDSCH).

Next, the transmission unit 20 of the base station device 10 transmitsthe downlink transmission data including data destined to the mobilestation device 50 to the mobile station device 50 via the downlinkshared channel (PDSCH) (step S205).

The control data extraction unit 56 of the mobile station device 50performs cyclic redundancy checking (CRC) on the reception data of thereception unit 63 in step S204.

The step S202, the steps S203 and S204, and the step S205 are executedin parallel.

Upon detection of the random access response message to the preamblepreviously transmitted by itself, the mobile station device 50 discardsthe synchronization timing deviation information included in the randomaccess response message, thus not performing the uplink timing alignment(uplink synchronization processing) and not performing the reset of thetimer by use of the synchronization timing deviation informationincluded in the random access response message. This preventsinconsistency occurring between the base station device and the mobilestation device in terms of the uplink synchronous/asynchronous status.Since no confirmation is secured as to whether or not the detectedtiming deviation information derives from the preamble by itself, it isunadvisable to perform timing alignment. Since the reset of the timercauses inconsistency between the base station device and the mobilestation device with respect to the synchronization sustainable time, itis advisable to maintain the present operation of the timer. The basestation device and the mobile station device are supposed to maintainthe previous uplink synchronous/asynchronous status prior to the randomaccess. This eliminates the necessity of needlessly executing the errorrecovery process.

The transmission unit 62 of the mobile station device 50 transmits theL2/L3 message including the C-RNTI (random access information) to thebase station device 10 via the uplink shared channel (PUSCH) designatedby the scheduling information included in the random access responsemessage (message M3) (step S206). The random access information includesthe information representative of the uplink resource request and theuplink buffer status representative of the amount of uplink data storedin the uplink buffer.

Upon detecting the C-RNTI for itself with the control data extractionunit 56, the transmission unit 62 of the mobile station device 50transmits a HARQ feedback including the information of ACK or NACK tothe base station device 10 via the uplink control channel (PUCCH) (stepS207). The step S206 and the step S207 are executed in parallel.

The transmission unit 20 of the base station device 10 transmits theuplink grant including the resource assignment and the C-RNTI to themobile station device 50 via the downlink control channel (PDCCH) (stepS208). The reception unit 63 of the mobile station device 50 receivesthe uplink grant transmitted thereto from the base station device 10.

The control data extraction unit 56 of the mobile station device 50makes a decision as to whether or not the C-RNTI for the mobile stationitself is included in the reception data of the reception unit 63 instep S208, wherein when the C-RNTI for the mobile station itself isincluded, it recognizes the resource position and the modulation methodwith respect to the subsequent uplink shared channel (PUSCH) based onthe resource assignment information.

Next, upon detecting the C-RNTI for the mobile station itself in theuplink grant, the transmission unit 62 of the mobile station device 50transmits, to the base station device 10, the uplink data including thedata destined to the base station device via the uplink shared channel(PUSCH) (step S209).

In the execution of the aforementioned steps S201 to S209, the mobilestation device 50 performs uplink communication with the base stationdevice 10 by use of the resource assignment included in the uplink grantreceived by the reception unit 63 in step S208 while performing downlinkcommunication with the base station device 10 by use of the resourceassignment included in the downlink control data received by thereception unit 63 in step S204.

In addition, the base station device 10 performs uplink communicationwith the mobile station device 50 by use of the resource assignmentincluded in the uplink grant transmitted by the transmission unit 20 instep S208 while performing downlink communication with the mobilestation device 50 by use of the resource assignment included in thedownlink control data transmitted by the transmission unit 20 in stepS204.

The base station device cannot recognize which mobile station makes arandom access until acquiring the random access information transmittedthereto with the message M3. Therefore, it handles the transmission ofthe random access response and the downlink data to the mobile stationdevice in parallel.

In a random access to the base station device, the mobile station devicein the uplink synchronous status monitors the downlink control channel(PDCCH) while verifying both the C-RNTI designating the downlink controldata or the uplink grant and the RA-RNTI designating the random accessresponse control data.

The mobile station device does not transmit ACK/NACK when thetransmission timing of ACK/NACK for the downlink data scheduled by theC-RNTI overlaps the transmission timing of the above message M3. Sincethe mobile station device performs single-carrier transmission on uplinkdata to the base station device, it is impossible to concurrentlytransmit the resource of ACK/NAC and the resource of the message M3. Thetransmission of uplink data precedes the transmission of downlink datawhich has enough resources compared to uplink data and isre-transmittable. In this case, the mobile station device does nottransmit ACK/NACK to the base station device.

According to another method, the ACK is transmitted in the case of asuccessful result of the cyclic redundancy checking (CRC) on downlinkdata, while the message M3 is transmitted to the base station deviceonly in the case of a failed result of the cyclic redundancy checking(CRC) on downlink data. The mobile station device exploits the nextchance (or retransmission timing) to transmit the message M3. The basestation device performs efficient communication in such a way thatretransmission is performed upon detection of transmission of NACK fordownlink data while retransmission becomes needless upon detection ofACK.

FIG. 6 is a flowchart showing a processing of the base station device 10according to the embodiment of the present invention.

FIG. 6 concretely shows the processing of the base station device 10shown in FIG. 5. Upon reception and detection of the preamble from themobile station device in the random access (steps S301, S302), the basestation device generates the random access response control data andrandom access response data used for the random access response (stepS303). It sets the random access response control data to the downlinkcontrol channel (PDCCH) (step S307) while setting the random accessresponse data to the downlink shared channel (PDSCH) (step S308), thustransmitting them to the mobile station device.

The base station device transmits downlink data to the mobile stationdevice in parallel with the execution of the random access process. Thebase station device performs scheduling to the mobile station device(step S304) so as to determine which mobile station the downlink datashould be transmitted to (step S305).

It generates downlink control data and downlink transmission data usedfor transmission of downlink data. It sets the downlink control data tothe downlink control channel (PDCCH) (step S307) while setting thedownlink transmission data to the downlink shared channel (PDSCH) (stepS308), thus transmitting them to the mobile station device.

Since the base station device can not be notified of which mobilestation device made a random access, the downlink data and the randomaccess response may be concurrently assigned to the mobile stationdevice.

The base station device may transmit the uplink grant and the randomaccess response in parallel. That is, the uplink grant and the randomaccess response may be concurrently assigned to the mobile stationdevice.

FIG. 7 is a flowchart showing a processing of the mobile station device50 according to the embodiment of the present invention.

FIG. 7 concretely shows the processing of the mobile station device 50shown in FIG. 5. After completion of transmission of the preamble in theasynchronous random access (step S401), the mobile station devicemonitors the downlink to receive the random access response message fromthe base station device. First, the mobile station device makes adecision as to whether or not it transmits the preamble in the uplinksynchronous state (step S402). In the present embodiment this indicateswhether or not the mobile station device in the uplink synchronousstatus transmits the preamble for the purpose of the uplink resourcerequest.

When it is determined that it is not in the uplink synchronous state,the mobile station device monitors the RA-RNTI (steps S403, S404). Whenthe RA-RNTI is not detected in a certain period of time or when thedetected RA-RNTI does not include the preamble ID number (or random ID)previously transmitted by itself, a timeout is declared (step S407) sothat the mobile station device repeats random access again.

Upon detection of the RA-RNTI in step S404, the mobile station deviceperforms cyclic redundancy checking (CRC) on the downlink shared channel(PDSCH) of the resource block which is assigned and designated by theRA-RNTI, thus performing success/failure determination on the cyclicredundancy checking (CRC). In the case of a failure determination of thecyclic redundancy checking (CRC), the mobile station device repeatsmonitoring on the RA-RNTI again (steps S403, S404).

In the case of a success determination of the cyclic redundancy checking(CRC), the mobile station device makes a decision as to whether or notthe same preamble ID number of the preamble previously transmitted byitself in step S401 is included in the downlink shared channel (PDSCH)which successfully passes the cyclic redundancy checking (CRC) (stepS406).

When the same preamble ID number of the preamble previously transmittedby itself is included, the mobile station device acquires and processesthe random access response message from the downlink shared channel(PDSCH) together with the preamble ID number (step S408). That is, theuplink synchronization is corrected based on the synchronization timingdeviation information (step S408); the L2/L3 message serving as themessage M3 is generated (step S409); and then, the message M3 istransmitted to the base station device (step S410).

When the same preamble ID number of the preamble previously transmittedby itself is not included, the mobile station device monitors theRA-RNTI (steps S403, S404).

Upon the determination in step S402 that the mobile station device makesa random access with the uplink synchronization by way of transmissionof the preamble in step S401, the mobile station device monitors theC-RNTI and the RA-RNTI (step S411). When the RA-RNTI is not detected ina certain period of time or when the detected RA-RNTI does not includethe preamble ID number (or random ID) previously transmitted by itself,a timeout is declared (step S423) so that the mobile station devicerepeats the random access again (step S401).

Upon detecting one of the C-RNTI and the RA-RNTI in the downlink controlchannel (PDCCH), the mobile station device further verifies whether theother is designated for the downlink control channel (PDCCH) (stepS412).

Upon detection of the C-RNTI in step S412, the mobile station deviceperforms demodulation on the downlink shared channel (PDSCH) in theresource block which is assigned by the detected C-RNTI. Then, itperforms cyclic redundancy checking (CRC) on the downlink shared channel(PDSCH), thus performing success/failure determination (step S414). Inthe case of a success determination, an ACK for HARQ is generated (stepS420) and is then transmitted to the base station device (step S422),while in the case of a failure determination, a NACK for HARQ isgenerated (step S419) and is then transmitted to the base station device(step S422).

Upon detection of the RA-RNTI in step S412, the mobile station deviceperforms demodulation on the downlink shared channel (PDSCH) in theresource block which is assigned by the RA-RNTI. Then, it performscyclic redundancy checking (CRC) on the downlink shared channel (PDSCH),thus performing success/failure determination on the cyclic redundancychecking (CRC) (step S413). Upon a failure determination on the cyclicredundancy checking (CRC), the mobile station device repeats monitoringon the RA-RNTI again (step S411).

Upon a success determination on the cyclic redundancy checking (CRC),the mobile station device makes a decision as to whether or not the samepreamble ID number of the preamble previously transmitted by itself isincluded in the downlink shared channel (PDSCH) (step S416).

Upon the determination in step S416 that the same preamble ID numberpreviously transmitted by itself is included, the mobile station deviceacquires and processes the random access response message from thedownlink shared channel (PDSCH) together with the preamble ID number(step S417). Herein, the uplink synchronization is not corrected basedon the synchronization timing deviation information (step S417); theL2/L3 message serving as the message M3 is generated (step 418); andthen, it is transmitted to the base station device (step S422).

Upon the determination in step S416 that the same preamble ID numberpreviously transmitted by itself is not included, the mobile stationdevice monitors the RA-RNTI (step S411).

Upon detection of the C-RNTI and the RA-RNTI in the downlink controlchannel (PDCCH) of the same sub-frame, the mobile station deviceperforms demodulation on the downlink shared channel (PDSCH) in theresource block designated by the C-RNTI while performing demodulation onthe downlink shared channel (PDSCH) in the resource block designated bythe RA-RNTI (step S415). This achieves an uninterrupted execution on thedownlink data reception and uplink resource request. In this case, itperforms the process regarding the detected C-RNTI and the processregarding the detected RA-RNTI in parallel.

According to another method adapted to the mobile station device whichdoes not have the capability of demodulating two downlink sharedchannels (PDSCH), it may perform demodulation on only the downlinkshared channel (PDSCH) in the resource block designated by the RA-RNTIor only the downlink shared channel (PDSCH) in the resource blockdesignated by the C-RNTI. This may diminish the packaging complexity ofthe mobile station device. When the prescribed capability ispredetermined for the mobile station device or when the capability ofthe mobile station device is predetermined by specifications, it ispossible to directly make a determination whether to demodulate only thedownlink shared channel (PDSCH) in the resource block designated by theRA-RNTI, determination whether to demodulate only the downlink sharedchannel (PDSCH) in the resource block designated by the C-RNTI, ordetermination whether to demodulate both of them without problem; hence,it is possible to omit step S415 in the drawing.

When the transmission timing of the ACK/NACK for downlink data scheduledby the C-RNTI overlaps with the transmission timing of the message M3designated by the random access response, the mobile station device isrectified not to transmit the ACK/NACK (step S421). For the purpose ofuplink single-carrier transmission, the mobile station device cannotconcurrently transmit the resource of the ACK/NACK and the resource ofthe message M3 to the base station device. To process in parallel inuplink synchronization, the condition of the transmission timingsoverlapping with each other occurs without depending upon data beingdetected in the downlink control channel (PDCCH).

The transmission of uplink transmission precedes the transmission ofdownlink data which has enough resources compared to uplink data and isre-transmittable. In this case, the mobile station device does nottransmit the ACK/NACK.

According to a further method, it transmits the ACK in the case of asuccess determination on the cyclic redundancy checking (CRC) ofdownlink data while transmitting the message M3 to the base stationdevice in the case of a failure determination on the cyclic redundancychecking (CRC) of downlink data. The mobile station device transmits themessage M3 at the next chance (or retransmission timing). It is possibleto perform highly efficient communication since the base station deviceperforms retransmission when the ACK for downlink data is nottransmitted thereto while it does not necessarily perform retransmissionupon detection of the ACK.

According to the above embodiment of the present invention, when thetransmission unit 62 of the mobile station device 50 in the uplinksynchronous status transmits the preamble to the base station device 10via the random access channel, the mobile station device 10 monitors thedownlink control channel (PDCCH) while verifying both of the C-RNTI fordesignating an uplink grant or downlink control data transmitted by thebase station device 10 and the RA-RNTI for designating random accessresponse control data; hence, it is possible to perform the randomaccess processing between the mobile station device 50 and the basestation device 10 without interrupting communication between the mobilestation device 50 and the base station device 10, and thus it ispossible to perform highly efficient communication between the mobilestation device 50 and the base station device 10.

According to a variation of the embodiment of the present invention,only the downlink control channel (PDCCH) is subjected to monitoringwith verification on only the RA-RNTI for designating random accessresponse control data during a random access involved in the uplinksynchronous status, wherein a method for continuing the uplinksynchronous status will be described below.

FIG. 8 is a sequence diagram showing a processing of the radiocommunication system according to a variation of the embodiment of thepresent invention. The sequence diagram of FIG. 8 shows the processingregarding an uplink resource request by way of a contended randomaccess. This shows the processing issuing the uplink resource requestdue to the occurrence of data to be transmitted in the mobile stationdevice in the uplink synchronous status. The mobile station devicetransmits the preamble, whose preamble ID number is randomly selectedfrom among preamble IDs available for the contended random access, tothe base station device (step S501).

The base station device detects the above preamble transmitted by themobile station device. Herein, the preamble is a signal pattern suitedto the preamble ID number, wherein the base station device detects thepreamble upon detection of the reception signal matching the signalpattern of the preamble ID number.

The random access response transmitted from the base station device tothe mobile station device, which is illustrated in step S02 of FIG. 11,is constituted of the random access response control data transmittedvia the downlink control channel (PDCCH) (step S502) and the randomaccess response data transmitted via the downlink shared channel (PDSCH)(step S503).

The base station device transmits the random access response controldata including the RA-RNTI and the resource assignment information tothe mobile station device via the downlink control channel (PDCCH) (stepS502), thus designating the resource block (PDSCH) for allocating therandom access response data.

In addition, the base station device transmits the random accessresponse data in the resource block designated by the random accessresponse control data (step S503).

The mobile station device transmitting the preamble to the base stationdevice receives the random access response control data and the randomaccess response data from the base station device (steps S502, S503).The mobile station device receives the random access response messagefor the preamble previously transmitted by itself by way of acquisitionof the message whose preamble ID number which is included in the randomaccess response data matches the preamble ID number of the preamblepreviously transmitted by itself. The mobile station device discards thesynchronization timing deviation information included in the randomaccess response message, thus not performing the uplink timing alignment(uplink synchronization process) and not performing the reset of thetimer by use of the synchronization timing deviation informationincluded in the random access response message. This preventsinconsistency occurring between the base station device and the mobilestation device in terms of the uplink synchronous/asynchronous status.It is unadvisable to perform the timing alignment in the case of thecontended random access since no confirmation is secured as to whetherthe detected synchronization timing deviation information derives fromthe preamble previously transmitted by itself. Since the reset of thetimer causes inconsistency occurring between the base station device andthe mobile station device with respect to the synchronizationsustainable time; hence, it is advisable to maintain the presentoperation of the timer. The base station device and the mobile stationdevice are supposed to maintain the previous uplinksynchronous/asynchronous status prior to the random access. Thiseliminates the necessity of needlessly executing the error recoveryprocess.

The mobile station device transmits the L2/L3 message including theC-RNTI (random access information) to the base station device (messageM3) in the resource designated by the scheduling information included inthe random access response message (step S504). The random accessinformation includes the information representative of the uplinkresource request and the uplink buffer status representative of theamount of uplink data stored in the uplink buffer.

The base station device transmits the uplink grant suited to the uplinkresource request to the mobile station device via the downlink controlchannel (PDCCH) (step S505). The mobile station device receiving theuplink grant transmits uplink data to the base station device via theuplink shared channel (PUSCH) (step S506).

In the aforementioned embodiment, programs implementing the functions ofthe base station device 10 (FIG. 1) including the data control unit 11,the OFDM modulation unit 12, the scheduling unit 13, the channelestimation unit 14, the DFT-S-OFDM (DFT-Spread-OFDM) demodulation unit15, the control data extraction unit 16, the preamble detection unit 17,and the radio unit 18 as well as the functions of the mobile stationdevice 50 (FIG. 2) including the data control unit 51, the DFT-S-OFDMmodulation unit 52, the scheduling unit 53, the OFDM demodulation unit54, the channel estimation unit 55, the control data extraction unit 56,the synchronization correction unit 57, the preamble generation unit 58,the preamble selection unit 59, and the radio unit 60 are stored incomputer-readable storage media, so that programs stored in storagemedia are loaded into and run by a computer system, thus controlling thebase station device 10 and the mobile station device 50. Herein, theterm “computer system” may embrace hardware such as the OS andperipheral devices.

The term “computer-readable storage media” refers to portable media suchas flexible disks, magneto-optical disks, ROM, and CD-ROMs as well asstorage devices such as hard-disk units built in computer systems. Inaddition, the term “computer-readable storage media” may embrace mediafor temporarily and dynamically retaining programs, e.g. communicationlines for transmitting programs, such as networks, the Internet, andtelephone lines as well as media for retaining programs in prescribedperiods, such as internal volatile memories of computer systems servingas servers and clients. The aforementioned programs may achieve a partof the aforementioned functions, or they are combined with pre-installedprograms of computer systems so as to achieve the aforementionedfunctions.

As described above, the radio communication system according to oneembodiment of the present invention is a radio communication systemincluding a base station device and a mobile station device, wherein themobile station device includes a preamble transmission unit whichtransmits a random access preamble to the base station device, adownlink control channel reception unit which receives a downlinkcontrol channel, and a determination unit which makes a determination asto whether or not the downlink control channel includes response controldata, which the base station device transmits in response to the randomaccess preamble transmitted by the preamble transmission unit and makesa determination as to whether or not the downlink control channelincludes an uplink grant or downlink control data destined thereto, andwherein the base station device includes a preamble reception unit whichreceives the random access preamble from the mobile station device, adownlink control channel transmission unit which transmits the downlinkcontrol channel, a response control data transmission unit whichtransmits response control data via the downlink control channel whenthe preamble reception unit receives the random access preamble, and adownlink control data transmission unit which transmits downlink controldata including a downlink resource assignment via the downlink controlchannel.

The mobile station device according to one embodiment of the presentinvention is a mobile station device which performs radio communicationwith a base station device and which includes a preamble transmissionunit which transmits a random access preamble to the base stationdevice, a downlink control channel reception unit which receives adownlink control channel, and a determination unit which makes adetermination as to whether or not the downlink control channel includesresponse control data, which the base station device transmits inresponse to the random access preamble transmitted by the preambletransmission unit, and makes a determination as to whether or not thedownlink control channel includes an uplink grant or downlink controldata destined thereto.

A program according to one embodiment of the present invention causes acomputer of a mobile station device performing radio communication witha base station device to serve as a preamble transmission unit fortransmitting a random access preamble to the base station device, adownlink control channel reception unit for receiving a downlink controlchannel, and a determination unit for making a determination as towhether or not the downlink control channel includes response controldata, which the base station device transmits in response to the randomaccess preamble transmitted by the preamble transmission unit, and formaking a determination as to whether or not the downlink control channelincludes an uplink grant or downlink control data destined thereto.

A radio communication method according to one embodiment of the presentinvention is a radio communication method using a base station deviceand a mobile station device, wherein the mobile station deviceimplements a preamble transmission process which transmits a randomaccess preamble to the base station device, a downlink control channelreception process which receives a downlink control channel, and adetermination process which makes a determination as to whether or notthe downlink control channel includes response control data, which thebase station device transmits in response to the random access preambletransmitted in the preamble transmission process, and makes adetermination as to whether or not the downlink control channel includesan uplink grant or downlink control data destined thereto, and whereinthe base station device implements a preamble reception process whichreceives the random access preamble from the mobile station device, adownlink control channel transmission process which transmits thedownlink control channel, a response control data transmission processwhich transmits response control data including an assignment of anuplink resource, which is not assigned to another mobile station device,to the mobile station device upon reception of an uplink resourcerequest in a resource request reception process, a response control datatransmission process which transmits the response control data via thedownlink control channel upon reception of the random access preamble inthe preamble reception process, and a downlink control data transmissionprocess which transmits the downlink control data including a downlinkresource assignment via the downlink control channel.

The embodiment of this invention is described in detail with referenceto the drawings, wherein the detailed constitution is not necessarilylimited to the embodiment so that the claims may embrace designs whosescopes do no depart from the scope of the invention.

INDUSTRIAL APPLICABILITY

The present invention is applicable to mobile station devices and radiocommunication systems performing highly efficient communications betweenmobile station devices and base station devices.

1. A radio communication system including a mobile station device whichtransmits a random access preamble to a base station device and resets atimer managing an uplink synchronous status based on timing deviationinformation included in a random access response which the base stationdevice transmits in response to the transmitted random access preamble,and the base station device which receives the random access preamblefrom the mobile station device and transmits a random access responseincluding timing deviation information calculated based on a receptiontiming of the random access preamble, wherein, in the uplink synchronousstatus, upon reception of a random access response including timingdeviation information transmitted from the base station device inresponse to a random access preamble whose preamble ID is randomlyselected by the mobile station device, the mobile station device doesnot perform to reset the timer based on reception of the timingdeviation information.
 2. The radio communication system according toclaim 1, wherein the uplink synchronous status is sustained until thetimer expires.
 3. A mobile station device which transmits a randomaccess preamble to a base station device and resets a timer managing anuplink synchronous status based on reception of timing deviationinformation included in a random access response that the base stationdevice transmits in response to the transmitted random access preamble,wherein, in the uplink synchronous status, upon reception of a randomaccess response including timing deviation information whose preamble IDis randomly selected by the mobile station device, the mobile stationdevice does not perform to reset the timer based on reception of thetiming deviation information.
 4. The mobile station device according toclaim 3, wherein the uplink synchronous status is sustained until thetimer expires.
 5. A radio communication system including a mobilestation device which manages a predetermined time as an uplinksynchronous status by a timer after receiving a timing deviationinformation from the base station device, resets the timer based onreceiving timing deviation information, and the base station devicewhich transmits the timing deviation information to the mobile stationdevice, wherein, in the uplink synchronous status, the mobile stationdevice does not perform to reset the timer based on timing deviationinformation included in a random access response which is a response toa random access preamble whose preamble ID is randomly selected.
 6. Amobile station device which manages a predetermined time as an uplinksynchronous status by a timer after receiving a timing deviationinformation from the base station device, resets the timer based onreceiving timing deviation information, wherein, in the uplinksynchronous status, the mobile station device does not perform to resetthe timer based on timing deviation information included in a randomaccess response which is a response to a random access preamble whosepreamble ID is randomly selected.
 7. A processing method of a mobilestation device which transmits a random access preamble to a basestation device and resets a timer managing an uplink synchronous statusbased on reception of timing deviation information included in a randomaccess response that the base station device transmits in response tothe transmitted random access preamble, wherein, in the uplinksynchronous status, upon reception of a random access response includingtiming deviation information whose preamble ID is randomly selected bythe mobile station device, the mobile station device does not perform toreset the timer based on reception of the timing deviation information.8. A processing method of a mobile station device which manages apredetermined time as an uplink synchronous status by a timer afterreceiving a timing deviation information from the base station device,resets the timer based on receiving timing deviation information,wherein, in the uplink synchronous status, the mobile station devicedoes not perform to reset the timer based on timing deviationinformation included in a random access response which is a response toa random access preamble whose preamble ID is randomly selected.